Effect of DEP on the expression of IL-1β-induced hBD-2 mRNA in A549 cells. (A) A549 cells were transfected with the luciferase plasmid containing hBD-2 promoter for 20 h. After pre-treatment with 50 pg/ml IL-1β for 1 h, the cells were exposed to 5–200 μg/ml of DEP for 24 h. The cells were harvested and assayed for luciferase activity as described in Methods. Luciferase activities are expressed as a fold-activation relative to the IL-1β only-treated control. Values are mean ± SD of five independent experiments. *, P < 0.005. Also, A549 cells were stimulated with 50 pg/ml IL-1β for 1 h and then treated with 5–200 μg/ml of DEP for 20 h. Total RNA was extracted and RT-PCR (B) and real-time quantification PCR (C) were performed using specific primers for hBD-2 and β-tubulin. The hBD-2 signals were normalized to β-tubulin and are presented in arbitrary units (A.U.).